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Titolo:
The kinetics and phase patterns in a ternary mixture coupled with chemicalreaction of A+B-Gamma 1 reversible arrow C-Gamma 1
Autore:
Liu, B; Tong, CH; Yang, YL;
Indirizzi:
Fudan Univ, SMEC, Key Lab Mol Engn Polym, Dept Macromol Sci, Shanghai 200433, Peoples R China Fudan Univ Shanghai Peoples R China 200433 nghai 200433, Peoples R China
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 41, volume: 105, anno: 2001,
pagine: 10091 - 10100
SICI:
1520-6106(20011018)105:41<10091:TKAPPI>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
COPOLYMER-HOMOPOLYMER MIXTURES; POLYMER BLENDS; BINARY-MIXTURES; BLOCK-COPOLYMER; SEPARATION; DYNAMICS; SURFACTANT; SIMULATIONS; LIGHT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Yang, YL Fudan Univ, SMEC, Key Lab Mol Engn Polym, Dept Macromol Sci, Shanghai 200433, Peoples R China Fudan Univ Shanghai Peoples R China 200433 433, Peoples R China
Citazione:
B. Liu et al., "The kinetics and phase patterns in a ternary mixture coupled with chemicalreaction of A+B-Gamma 1 reversible arrow C-Gamma 1", J PHYS CH B, 105(41), 2001, pp. 10091-10100

Abstract

In this paper, the phase separation of A, B, and C ternary mixtures coupled with the chemical reaction of A + B (Gamma1 -->)(<-- Gamma -1) C is investigated numerically on the basis of the modified time-dependent Ginzburg-Landau (TDGL) equation. The simulation results showed that, depending on the rate constant of chemical reaction and the compatibility between the components, very complicated phase patterns could be obtained. It is found that when the compatibility of A and B is Poor and C has good compatibility with A/B, in the early stage of phase evolution, the phase separation between A and B pushes C to the interface between A- and B-rich domains. However, when A and B are compatible while C and A/B are incompatible, in the early stage of phase evolution, C-rich spherical droplets are immersed in the A/B continuous phase. As evolution goes on, the phase separation of A and B takesplace and pushes C droplets to the interface between A- and B-rich domains. It is also found that the phase evolution depends on the competition between chemical reaction and phase separation. In the case of a relatively large reaction rate constant, the effect of chemical reaction is dominant, thephase separation between C and A/B is inhibited, and the phase separation between A and B takes place. As the phase separation of A and B proceeds, Cdecomposes into A and B rapidly, resulting in the phase pattern of small amount of C distributed along the interface between A- and B-rich domains. As the reaction rate constant gradually decreases, the effect of chemical reaction is diminishing. In the late stage of phase separation, the concentration of C increases as the rate constant of chemical reaction decreases, and the C-rich phase changes from dispersed droplets to the continuous thin phase. Therefore, the phase separation between A and B can only be confined in small regions, resembling the case of binary mixture of A and B homopolymers with AB diblock copolymers. The above results reveal importantly that due to the phase separation between the components A, B, and C, the global equilibrium, which exists in the homogeneous mixture, does not exist in thephase separating system. The overall volume fraction of C could be either lower or higher than the equilibrium value for the homogeneous mixture, depending on the compatibility between the components and the rate constant ofcoupled chemical reaction.

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Documento generato il 03/04/20 alle ore 13:59:11